Tube forming apparatus



April 18, 1950 F v COLLlNS 2,504,500

TUBE FORMING APPARATUS Filed Maron 2, 1946' gn?, 7 ,JZ-dem.' /f 60%@ Patented Apr. 18, 1950 TUBE FORMING APPARATUS Fred V. Collins, Des Plaines, IIL, assigner to Wilv liam F. Stahl, Chicago, Ill.

Application March 2, 1946, Serial No. 651,642

ship. At the destination, considerable space is` required for storing.

An object of the present invention is to provide a simple apparatus and method which may be employed at the point of destination, where the tubes are to be used, for forming tubes from fiat stock and as the tubes are needed. A further object is to provide an apparatus and a method for forming tubes directly from flat stock supported upon a reel so that a large quantity of tubes can be formed rapidly from a relatively small and compact roll of iiat Web stock. Yet another object is to provide means whereby high frequency radio waves may be employed for the sealing of a tube formed continuously from atstock in an effective manner. Other specific objects and advantages will appear as the specification proceeds.

The invention is illustrated, in a preferred embodiment, by the accompanying drawing, in which- Figure 1 is a broken side view in elevation of apparatus embodying my invention; Fig. 2, an enlarged longitudinal. sectional view of the mandrel and the electronic foot; Fig. 3, a transverse sectional view, the section being taken as indicated at line 3 of Fig. 2; Fig. 4, a transverse sectional view, the section being taken as indicated at line 4 of Fig. 2; and, Fig. 5, a perspective or diagrammatic view of the web as it is formed into a tube and united by fusing.

In the illustration given, I designates a frame vwhich may be of any suitable type or construction. Upon the frame I0 is mounted on one side a standard II and on the other side a support or tail-stock I2. Between the members -II and I2 and to the rear thereof is an apron or shield I3 of thin metal. If desired, the web or shield I3 may be omitted. Supported by the members II and I2 is a radio frequency generator I4 which may be of any suitable type or construction. The

radio frequency generator is noil claimed per se herein and, therefore, is not described in detail.

I prefer to employ a mandrel I as a means for supporting the web when it is formed into a tube. The mandrel I5 is preferably supported 1 Claim. (CL 154-42) 2 by the tail-stock member I2 or formed integrally therewith, a slot being formed at I3 in the tailstock I2 to permit the web I8 to pass therethrough. It will be understood that any suitable means may be provided for suspending or supporting mandrel I5 so that the lower portion of the mandrel at the rear will be open forI contact with the web I6 as it is fed forwardly to enclose the mandrel.

The forward end of mandrel I5 extends between two rollers I1 and I8 which are preferably provided with a resilient sleeve I9 of rubber or other suitable material. One or both of the wheels I'I and I8 may be driven to feed the material I6, now in tubular form, along the mandrel I 5. In the illustration given, a motor 20 is shown, supported by frame I0 and driving a sprocket 2|. ,A chain 22 connects sprocket 2| with a sprocket 23 xed on the shaft of wheel I'I. Wheel I'I may be equipped with a gear meshing with a gear (not shown) fixed to wheel I8 for simultaneously driving wheel I8. It is preferred to have wheels I1 and I8 synchronized in their rotation.

Mounted upon frame III is a reel rack 24 supporting a shaft 25 carrying the roll of fiat material I6. A guide rack 26, equipped with rollers 21 and 218, is supported just forwardly of the rack 24 and serves to guide the web IIB toward the bottom of the mandrel I5.

Mounted upon a platform 23, carried by the frame III, is an electronic housing member 30 which comprises the bottom wall 3l, side walls 32 and rear frame 33. Such walls may be formed of steel or other suitable material. The top wall 34 is preferably formed of a non-conducting material such as polystyrene, etc. The bottom and side walls are each equipped with a sleeve member 36 providing a guide for a stem 31 which is equipped at its top with a roller 38. A spring 33 normally urges the roller inwardly toward the mandrel.

Extending through the top wall 34 and terminating at a point just above the mandrel. I5 is a roller 4|) forming an electronic foot. The roller 40 engages the web I6 and to hold the overlapping sides thereof together during the action of the high frequency radio waves in the fusing operation. It will be understood that the electronic shoe 40 is connected with the radio frequency generator I4.

At the rear of the housing 30 is a funnel block or tube-forming guide 4I. The guide 4I is provided with a forwardly and inwardly inclined opening 42 which guides the forwardly moving web I3 so as to form a tube as it enters the housins 30. I have found that satisfactory results are obtained when the member 4I is employed merely as a oating guide, resting freely upon the material Iiiv as it is fed forwardly upon mandrel I5. Figure 5 illustrates the gradual change in the form of the flat material I6 as it is fed forwardly to form the tube illustrated and with the sides of the material in overlapping relation.

The web or flat stock I6 may be formed of any suitable material which is responsive to the action of high frequency radio` waves and tends to fuse together portions of the vweb when brought into overlapping relation. The types of material thus responsive to such action are well known. Examples may be given as cellulose acetate, vinyl acetate or vinyl chloride (co-polymer).

Operation In the operation of the device, a roll of the material I6 may be placed upon the reel or shaft 26 so as to feed forwardly through the guide rack 26 and to envelopthe bottom portion of the mandrel l5. The advancing web is formed into a complete tube within the funnel block or guide 4| so that side portions of the material I6 overlap each other, as illustrated best in Fig. 5. The tube thus formed is held firmly in tubular shape by the pressure rollers 38 in housing 30 and the electronic foot 40 is effective in forming a straight fusion seam through the overlapping parts under the influence of high frequency radio waves. By overlapping I mean any structure in which the oppositesides of the tube, after the formation of the tube, lie against each other and are thus available for union through fusing.

' A relatively wide range of frequencies may be employed in bringing about the fusion operation. depending upon the type of material being united, its thickness, power factor and dielectric strength, etc. I have used frequencies of 200 megacycles effectively in the uniting of cellulose acetate. vinyl acetate, etc., in the usual tube thicknesses. The eil'ect of the high frequency radio waves is to bring about an internal change in the web so that a fusion occurs between the overlapping or adjacent walls, thus forming an integral seam or merging of the walls.

The operation is continuous, with flat material being fed under and then over the mandrel and the finished tube being drawn oil.' the opposite end of the mandrel under the pull exerted by the resilient tread of wheels I1 and I0.

The apparatus is extremely simple and compact and may be set up at the place of use with the result that at stock is usable to produce the tubes as they are needed.

a mandrel and by other means, while, at the same time, providing the overlapping edges. which may be `fused together.

While in the foregoing description, I have set forth one mode or method for employing the invention and have described the structure in great detail, it will be understood that such details may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

Apparatus for forming a tube from a fusible flat plastic sheet comprising an electrically conducting mandrel, guide means for directing said plastic sheet toward the mandrel and for wrapping the same longitudinally therearound to form a tube having a seam formed by overlapped edges of the sheet, a multi-sided frame surrounding the mandrel, a rotary, spring-urged contact electrode carried on one side of said frame and adapted to press on the lapped seam of the plastic tube, a plurality of spring-urged pressure rollers supported by said frame in spaced-apart positions on the periphery thereof operative to urge the plastic sheet into a tightly lapped position around the mandrel, a generator of radiofrequency electrical energy, and transmission line means for connecting the output of the generator to the contact electrode and the mandrel to impress a high-frequency electric eld therebetween-to fuse and integrate the lapped seam. FRED V. COLLINS.

REFERENCES CITED The following references are of record in the file 'of this patent:

UNITED STATES PATENTS Number Name Date 648,930 Doughty May 8, 1900 1,810,585 Young June 16, 1931 1,985,997 Keeran Jan. 1. 1935 2,125,758 Waters Aug. 2, 1938 2,170,364 l Bergstein Aug. 22, 1939 2,422,188 Epstein June 17, 1947 2,458,059 Christensen Jan. 4, 1949 OTHER REFERENCES An Electronic Sewing vMachine, by Cyril Hoyler, in Electronics of August, 1943, pp. 90-93, 160, 162, 164, 166 and 1.68. (Copy available in Division 20.) 

